Monday, February 10, 2014

My Homemade Barney Post.

This moved the main sheet cleat forward and up where it is easy to get hold of and also easy to move behind when tacking.  I used to have a problem with water coming up through the centerboard slot.  After a little silicone sealant was added around the lower edges here, all that stopped.  You can barely see two of the 4  holes I filled where the old fitting for the main sheet cleat used to be on the floor.  The whole arrangement comes apart easily with the help of an electric screwdriver.  I have since replaced that main sheet cleat with a ratcheting main sheet cleat similar to this (picture from another boat). 


Blue Line drawing of Deck Veiw Omega 14


Trim Angle of Jib, Trim Angle of Mainsail, Apparent wind, Heading, and Course Sailed are all relative.


Omega 14 Specifications


Trim Angle of Jib on the Omega 14 sailboat: Wigh fairlead in forward and aft positions.


Omega 14 "Auto Pilot"


Add power to your mainsail with a better bridle system.



Omega 14 Polar Diagram for wind speed vs. angle vs. boat speed

I went out sailing with my GPS and it recorded my track while I recorded the wind speed and boat speed.  The angle of the wind remained constant so when I got home I plotted the data above.

Saturday, February 8, 2014

Center of effort vs. Center of resistance on the sails of the Omega

When the sails are properly trimmed on a beat the center of effort of the wind will be a little behind
the center of resistance.  If you think about it you will realize that this will cause a slight weather helm.  If you let out the jib the CE moves back causing more weather helm.  If you ease the main you
naturally get more lee helm because the wind exerts more force on front of the boat and the boat pivots around the centerboard.



Omega 14
Standing Rigging

Standing rigging is the stuff that holds up the mast. It is the permanently secured rigging. In the Omega there are two shrouds (one on either side of the mast) and a forestay (or jibstay). When you step (put up) the mast you should set the tension on all of these just tight enough so the mast won’t flail around every time you go over a wave. If the mast is “banging” violently it is shock-loading the standing rigging and eventually it will fail.
the mast should be vertical (90 degrees from the horizon or to the seats) and not bent. Because the shrouds and stay join the mast at approximately the same place mast-bend is not a factor here. Of course the mast should be centered and straight from side to side too. By leveling the boat and putting a small weight on a halyard you should be able to tell when the mast is vertical (fore and aft as well as right and left). This is just a starting point and it can get very technical from here depending on the cut of your jib, sea and wind conditions you will be contending with. But one setting of the standing rig should cover you for a wide variety of conditions, and as I said, I’m trying to keep this simple.

The jib halyard is used to raise the jib and as you tension the jib halyard you will notice that it takes some tension off of the forestay. So the jib and the jib halyard are now supporting the mast in opposition to the shrouds because the shrouds are anchored somewhat aft of the mast.

When the main is up and you pull hard on the main sheet going to weather or when you have the boom vang on hard you are also putting additional tension on the forestay. These are things you should understand, but since I’m trying to get to the down and dirty hints for trimming sail when under way I will let you read more about that some winter evening when you can’t go sailing.

Mainsail Trim In Heavy Weather



Mainsheet Bridle Illustration

Note that the block in the center of the bridle is in a fixed position: tied on. I like this Bridle arrangement for several reasons.  Mainly, it allows you to bring the boom close to centerline of the boat without pulling the boom downward.  This allows you to keep some twist in the sail if you want it and allows you to point higher than when the block can ride back and forth on the bridle.  In the diagram the boom is away from centerline.  With the conventional arrangement the leach would be hooked to weather.  With this arrangement you can allow for some twist and improve power in a situation where it is needed.

Rigging and Trimming the Omega Sailboat

Omega 14 Sail Trim

I have read a book or two on sail trim. I raced Lightnings when I was young was always aware of how I trimmed my sails compared to my competitors. If you want to get technical and obsess about such things read “Sailing Theory and Practice” by C.A. Marchaj, or “Sail Power” by Wallace Ross or better still, “A manual of Sail trim” by Stuart Walker because he is a dinghy sailor and the information is applicable to the Omega 14.

But my objective here is to just cover the most salient points. And I will try to keep it simple. These are mostly the things you can look for quickly as you zip along to weather while still keeping one eye on the competition, looking for new wind, and adjusting weight distribution in the boat. This will be a series of articles where I will cover:
1. Standing Rigging
2. Bending on the sails and Halyard tension
3. Trimming the Main
4. Trimming the Jib
5. The ten essential things to remember to maximize speed

Standing rigging is the stuff that holds up the mast. In the Omega there are two shrouds (one on either side of the mast) and a forestay (or jibstay). When you step (put up) the mast you should set the tension on all of these just tight enough so the mast won’t flail around every time you go over a wave, and the mast is vertical (90 degrees from the horizon or to the seats) and not bent. Because the shrouds and stay join the mast at approximately the same place mast bend is not a factor at this point. Of course the mast should be centered and straight from side to side too. This is just a starting point and it can get very technical from here depending on the cut of your jib, sea and wind conditions you will be contending with. But one setting of the standing rig should cover you for a wide variety of conditions, and as I said, I’m trying to keep this simple.

The jib halyard is used to raise the jib and as you tension the jib halyard you will notice that it takes some tension off of the forestay. So the jib and the jib halyard are now supporting the mast in opposition to the shrouds because the shrouds are anchored somewhat aft of the mast.

When the main is up and you pull hard on the main sheet going to weather or when you have the boom vang on hard you are also putting additional tension on the forestay. These are things you should understand, but since I’m trying to get to the down and dirty hints for trimming sail when under way I will let you read more about that some winter evening when you can’t go sailing.

Jib
Sailing down wind and on a reach and more intuitive than beating (sailing as close to the wind as possible) and trimming usually involves letting the sail out until it starts to luff and pulling it back in to where it just barely stops luffing. In racing legs off the wind tactics and watching for changing wind directions are key and if you have a crew they should be able to trim the sails without much instruction. Having no spinnaker the Omega makes downwind sailing relatively easy. When running straight before the wind I let the main out all the way, try to wing out the jib, pull up the centerboard and heal the boat to windward.

When I raced Lightenings I obsessed and read everything I could about the Angle of Incidence (alpha). That is the angle between the direction of the apparent wind and a horizontal cord on the sail. So if you had control over how far outboard or inboard the jib cleat fairlead was, you could change this angle. Since the track that the jib fairleads ride on is fixed you probably won’t change this on the omega. Besides, since the jib sail is outside the shroud, pulling the sheet further toward the center of the boat will not help because the sail can’t come in further (laterally) than the shroud. Moving the sail track forward gives me an angle of 20.8 degrees and moving aft gives me an angle of 16.5 degrees. Most racing sailboats vary from 20 degrees (Lido, 5-0-5) to 8 or 9 degrees (12 meter). The Lightning seemed to have a sweet spot at about 10 degrees. So we are somewhat limited here in the Omega. Plus, you just can’t move the car aft without watching to see how it affects the jib.

The Jib
Start with just enough tension on the jib halyard to get the scallops or wrinkles out of the luff of the jib. You would add tension for heavy air. Sail close hauled and very slowly come up into the wind. If the jib luffs all along the luff at the same time the jib lead car is set correctly. If the top of the sail luffs first the car is set too far back and that makes the foot tight. If the car is too far forward the sail will luff nearer the foot of the sail. What you want is the angle of incidence of the sail about the same all along the front of the sail, and the leech of the sail should be an arch parallel to the mainsail. There are many factors involved but trimming the jib, once the mainsail is set should be easy. I have three telltales 6 inches back from the luff on the jib and watch for the inside upper telltales to just flutter every few seconds, telling me I am as close to the wind as I can get at that setting. The middle inside and outside telltales should be streaming if you are not stalled or pointing too high for optimum speed made good upwind. Google this subject for articles on how to sail with telltales, but understand that it is just one of the indicators that the boat is pointing to it’s best ability. Keep the boat flat so the transom nor the bow are dragging in the water. With any wind at all to keep the boat from heeling. You go faster with the sails perpendicular to the water. As the wind picks up your ability to hike out and adjust the sails will determine how flat you can keep the boat and how fast you go. While that is way more than I intended to say about the jib, it should give you a good starting point, and there are thousands of pages on-line and in books on the subject. However, you will have to sort through a lot of material to find what is applicable to the Omega.

When bending (attaching) the main sail start with enough halyard tension to keep wrinkles out of the luff. Like the jib, when the wind is stronger more tension is usually applied to get the sail flatter and the maximum curvature (“belly” of the sail further back). Same goes for the outhaul. More wind, more tension. Loosen on downwind runs if you are racing.
Let’s talk about going up wind: Beating into the wind. As the wind increases the boat will try to heal and you control this by putting your weight on the rail and hiking out. At the point where you can’t keep it flat any longer by hiking you will want to increase the “twist” in the upper part of the main sail. That is, the leech near the boom and the lower third of the mainsail will be closer to the angle of the boom, while the upper third will be falling off somewhat to leeward (down wind, pronounced LOO-word by old salts). Easing off the vang will help reduce the heeling forces up high and help you control the boat. The bottom of the sail will keep the boat pointing and driving to weather.

Specifically about the Omega mainsail. Like suggested for the Capri 14.2 (our bigger brother) I have the block on the bridle on the stern of the boat fixed. The boat usually comes with a block that rides back and forth (port and starboard) on the bridle. This is a problem in a light breeze (4 to 6 knots) , and even a gentle breeze (7 to 10 knots). It is a problem because as you tug on the mainsheet you are pulling the boom down toward the aft leeward corner of the transom. You should be pulling it to near center of the boat without pulling straight down on the leech. My boat with my sails doesn’t sail well with the leech hooked to weather. Think of the sailboat like a jet plane. You want to push air nearly straight back and as a result push the boat in the opposite direction.

I wish I knew some magic setting for the angle of the boom. I don’t. So called experts say the boom should be centered when sailing close hauled. I haven’t found that necessarily true and when I feel the boat getting sticky, or too much weather helm, I have found letting the boom out from center seems to get the boat moving and neutralizes the helm. This is something well worth experimenting with on your boat because sail shape and sea conditions will influence this.

Oh darn. I didn’t intend this to be such a long article. So lets get to some of the down and durty tips I think you can use.

7 tips to get you going faster:

Too much weather helm? Sail the boat flat and flatten the mainsail if you think there is too much weather helm. At times, the boat will develop weather helm, especially when in point mode, but an excessive tug on the tiller indicates that the boat is badly out of balance. The quick fixes: sail the boat flatter, raise the centerboard, decrease mast rake or flatten the mainsail.

When pointing look at middle batten. It should be about parallel with the center line of the boat when the boat isn't being overpowered with wind.
I have never found over-trimmng the main helps the Omega work better to weather.

The omega goes best sailed flat: “on its lines” as they say.

Test the jib and be sure that it breaks evenly, not at the top or bottom first. Three tilltales on the leach helps a lot.

In very light wind relax main and jib the luff tension. You may even see a few wrinkles along the luff and that is okay.

Going to weather most experts sail with the weather tiltale slightly stalled. It is tricky to keep the boat “in the grove” but experience will help you get this optimum angle at least most of the time.

Watch the competition and keep the boat moving. Beginners tend to pinch. Concentrating on sail trim at the expense of watching for new wind and what the leaders are doing can lead to poor results.